Kenwood KA 5700 amp and KT 5300 reciever

Through an estate auction, I recently aquired a vintage Kenwood KA 5700 amp and KT 5300 reciever. They were stored in the original boxes and athough a little dusty, seemed to be in pretty good condition.
I plugged them in and all the lights work and at first the meters worked but I've never been able to get any sound through any speakers. I have them hooked to a set of 8 ohm Infinity speakers, but haven't tried any others. The speakers are good; they work with other components.
I have tried all combinations of switches (there aren't that many) and different rca cables.
I don't see any obvious "reset" buttons or fuses. I've fooled with various components and stereos over the years and can usually figure this stuff out, but this one has me stumped unless it's just broke.
Any suggestions or comments that might help get this stereo working would be greatly appreciated, otherwise I have some junk to recycle.